Attachment for the tone arm of phonographs



Nov. 2 1926. 1,605,361

D. MARSH ATTACHMENT FOR THE TONE ARM 0F PHONOGRAPHS Filed March 29. 1923 INVENTOK M MM ATT NEY Patented Nov. 2, 1926.

UNETED STATEfi DANIEL MARSH, OF ER VINGTON, NEW JERSEY.

ATTACHMENT FOR THE TONE ARM F PI'IONOGRAPHS.

Application filed March 29, 1923.

The object of this invention is to provide an attachment for supporting a reproducer on the end of a tone arm of a phonograph so that lateral cut grooves can be easily traversed by the stylus, although the machine is of the type in which the tone arm is slowly turned by positive mechanical means. In other words, there is enough lost motion in the attachment to compensate for the difference in the pitch of the groove and the rate of travel of the tone arm.

The invention is illustrated in the accompanying drawing, in which Figure 1 is a top view of the attachment, showing part of a record and the end of a tone arm. Figure 2 is a section on line 2*2 in Figure 1. Fig ure 3 is a detail section of the connection be tween the tube and the pipe of the device, and Figure 4: is a section on line 44 in Figure 1.

In the drawing illustrates the tone arm, which this invention is adapted to be slid into so that it is a readily removable fixture. This tone arm is of the type used in machines such as the Edison, in which the tone arm is propelled by a mechanical means at a set rate of speed relative to the rotation of the record 11, and since the records are made for the machine, the travel of the tone arm and the revolution of the record are synchronized to such an extent as to not cause any excess lateral strain on the groove in the record. When playing lateral cut records, however, it is necessary to place a reproducer on the end of the tone arm and to give it freedom of action so that it can be propelled by the groove in the record irrespective ot the speed of the tone arm. hen these speeds are not equal the strain is taken up by the lost motion in the attachment.

The attachment consists of a pipe 12 which is fastened at one end by means of a connection to the tone arm, this connection having a swinging movement only in one plane, that is, a horizontal plane, and such a connection is shown in detail in Figure 2, the male member 13 fitting into the female member 14 and forming a modified ball joint, and the screw 15 acts not only to hold Serial No. 628,429.

the parts together, but to prevent any swinging movement except horizontally. The sleeve 16 is an extension on the part 1 1 which can be slid on the end of the tone arm and usually is fitted tight enough to hold the attachment in position without any other securing means, although in case of a loose fit such securing means can be provided.

The pipe 12 is in the form of an elbow, to the end of which is attached the U-shaped tube 17, the tube being attached to the pipe so that the tube has a swinging movement, but it can only swing in a vertical direction. The form of attachment illustrated comprises a sleeve 18 which fits into the end of the pipe 12 and holds the shoulder 19 in position when it abuts against the flange 20 on the inside of the pipe 12.

The pipe 12 is supplied with a slot 21, and the screw 22 passes through the pipe, the sleeve 18 and the end of it rests in the slot 21, but the parts are so disposed that when the device is on a phonograph in playing position the screw 22 is near one end of the slot 21, as shown in Figure 4, this being the upper end of the slot. The reason for this is that in playing the records are not always absolutely flat and they have a little unevenness, due to slight warping, which necessitates the reproducer floating up and down to a slight degree, and in case of renewing needles, etc., the reproducer must be swung all the way back to bring the needle uppermost. The screw 22 is far enough from the end 24 of the slot to permit this floating motion.

On the other hand, when the tone arm is raised, which is done in such machines as the Edison, when the tone arms gets to its inward limit of movement, in this construction such raising will cause the screw 22 to engage the end 24 ot the slot, and after the tone arm has gone a slight distance upward. the slot and the screw engage and the reproducer is lifted clear out the record, ready to be swung back to its initial starting point. The end of the tube 17 is provided with means for receiving any desired form of reproducer 25, as will be evident.

I claim: gether and to limit the swinging to a hori- An attachment for tone arms comprising. zontal plane, and a Ushaped tube rockably a sleeve having one member of a ball joint secured in the other end of the elbow. 10 at one end, a' pipe forming an elbow and In testimony that I claim the foregoing, 5 having the other member of the ball joint I have hereto set my hand, this 26th day on one end, a screw passing vertically of llizxreh, 1923.

through the ball joint to hold-the parts'to- DANIEL MAR-SH. 

